1. Field of the Invention
The invention relates to a rear stop device comprising a stop and/or gripping and/or measuring element.
2. The Prior Art
Generic rear stop devices, in particular with linear guides, are known from the prior art in a plurality of embodiments.
DE 697 22 935 T2 discloses a rear stop device, which is structured on the basis of a shearing lifting unit. Here two horizontally aligned stop fingers are arranged on a common guide rail running in a direction parallel to the sheet metal bending line, and can be displaced individually in this direction thereby. Said common guide rail is mounted on the shearing lifting units by two rods guided on the upper sides of the shearing lifting unit. By means of the connection of the two upper sides of the shearing lifting unit to a common guiding rod, on which the guide rail is mounted, it is ensured that the guide rail and the stop fingers attached onto the latter always maintain their horizontal alignment, even with a change in position height, and cannot be moved arbitrarily relative to their horizontal alignment. Two guiding elements are attached onto the lower side of the two sides of the shearing lifting unit which guiding elements can be moved in horizontal guide rails along the longitudinal direction of the guide rails, in order to achieve a height adjustment of the stop fingers. The described guide rails are partly designed as spindles in order to achieve the desire height adjustment by adjusting the guiding elements relative to one another. The described rear stop device is arranged directly on the machine frame of a bending machine. The stop section of said rear stop device, which is designed as a shearing hub, is thus limited to the half of the shearing lifting unit facing the bending press, as the stop finger cannot adopt a position in which it can be positioned on the side of the shearing lifting unit facing away from the bending press.
A disadvantage of the known embodiments which are controlled by means of linear drives is that there is a relatively high center of gravity of the whole rear stop device. In this way dynamic traversing movements or accelerations apply high forces on the drive units. DE 697 22 935 T2 solves this kinematic disadvantage by the said shearing lift, but has the disadvantage however that the shearing lift needs a lot of space and is limited in its stopping options. Therefore, it is not possible to achieve a space-saving installation in a metal sheet processing system, if the stop fingers need to have a traversing area that is as large as possible. Because of the limited positionability of the stop finger in stop direction there are only limited options for processing differently shaped metal sheets, or a very large amount of space is required. A further disadvantage is that the stop fingers can only be aligned in a horizontal direction. In this way the application is limited to flat metal sheets that are not prebent. The significant disadvantage of this is that the rear stop device is not adjusted to the required, free positionability in space which is necessary in modern processing machines.